NASA will seek a supplemental role aboard the European Space Agency’s (ESA) next two large astrophysics missions, including a new-generation X-ray telescope and a gravitational wave observatory.

“Both a large X-ray observatory and a large gravitational wave observatory are prioritized recommendations of the [2010 astrophysics] decadal survey, and so we are pursuing an opportunity to contribute and partner on ESA’s observatories,” said Paul Hertz, head of NASA’s astrophysics division, during a Dec. 3 meeting of the NASA Advisory Council’s science committee in Washington. “We will be setting up our discussions with ESA about a potential role for NASA in these missions.”

In November ESA announced its selection of the €1 billion ($1.37 billion) large-class missions, which include an advanced X-ray observatory slated to launch in 2028 that will study how ordinary matter assembles into galaxies and black holes grow and influence their surroundings. A second mission to follow in 2034 would search for ripples in the fabric of space-time created by celestial objects with strong gravity, such as pairs of merging black holes.

Although the launch dates for the European campaigns are more than a decade away, preparations for their development will start next year, including a call for mission concepts that will be used in soliciting proposals for the next-generation X-ray observatory.

Hertz said one of ESA’s ground rules for identifying the future large-class astrophysics missions was a requirement that they be developed independent of outside support. He said while ESA is capable of executing either mission without U.S. partnership, both would benefit from NASA participation.

“We can either add things which are enhancing or enabling to the mission, and any contributions will be on top of the €1 billion budget cap ESA set for the missions,” he said. “It allows us as an international community to do even more.”